The aim of the program is to examine a simple nervous system in order to understand completely its overall activity in terms of the activity of individual elements in the neuronal network that comprise the system. Several different experimental approaches will be used to achieve this understanding. The anatomy of the system will be studied in order to list the synapses in the structure; the electrical activity of individual cells will be recorded with microelectrodes; the pharmacology of neurons and muscle cells will be investigated; eventually a test will be made to see how the known behaviour of the animal is encoded by the output signals produced by the integration of neuronal activity in the system.